1. Field of the Invention
The present invention relates generally to a multi-function fluid flow monitoring apparatus having the unique capability of measuring fluid flow-related variables on the basis of outputs from any one or more of a plurality of different types of flow sensors. In accordance with the multi-functional features of the invention, the apparatus can also perform fluid monitoring operations and can be linked to a variety of external devices, such as an automatic sampling apparatus, a rain gauge, and the like, so as to operably cooperate with same. The apparatus also provides for the displaying, storing, and transferring of data relating to fluid flow measuring and monitoring operations.
More particularly, the invention relates to a compact unitary apparatus having a computer control system which calculates fluid flow-related variables on the basis of outputs from any desired one or more of a plurality of different types of flow sensors which may be selectively and interchangeably connected to the apparatus. By virtue of this multiple flow sensor capability, the user is provided with substantial flexibility in selecting a flow sensor system suitable for a given application, and then selectively switching to any desired one of a plurality of other types of sensor systems as the need arises. The user is also afforded the flexibility of investing in a basic apparatus including, for example, a single type of flow sensor, and then later expanding the range of use of the apparatus by investing in additional types of flow sensors which are all fully compatible with, and supported by, the basic apparatus.
The apparatus of the invention also comprises a text and graphics display which permits a user to selectively view stored data in either text or graphic formats. Stored data can also be transferred to a computer for manipulating data or producing hard copy reports.
The invention also provides a novel bubbler sensor type fluid flow monitoring system comprising a novel bubbler control module which overcomes power consumption and inaccuracy problems associated with conventional bubbler sensor systems. The bubbler sensor flow monitoring system according to the invention is incorporated in the multifunction flow monitoring apparatus with multiple flow sensor capability. In an alternative embodiment, the bubbler sensor flow monitoring system of the invention may be provided independently in a flow measuring device having only a single sensor capability.
The terminology "flow sensors" as used herein refers to various available types of sensors for detecting a variable related to fluid flow and producing an electrical output signal corresponding thereto. Such sensors include, but are not limited to, bubbler-type pressure sensors, submerged pressure transducers, ultrasonic sensors, area-velocity sensor systems, and the like.
The terminology "fluid flow-related variables" as used herein embraces a multitude of fluid flow parameters, including fluid level or depth, flow rate, velocity, total flow, i.e., the actual quantity of fluid discharged over a given time period, and the like.
In addition to the versatility afforded by the interchangeability of different flow sensors, the apparatus of the invention may also provide fluid monitoring capabilities similar to those described in the aforesaid U.S. Pat. No. 5,172,332, by attaching an appropriate fluid condition sensor to the fluid flow monitoring apparatus of the invention. These monitoring capabilities enable the apparatus to calculate the value of a given fluid condition on the basis of inputs from a fluid condition sensor. By way of example, such fluid conditions may include pH level, oxidation reduction potential ("ORP"), temperature, solution conductivity or resistivity, dissolved oxygen, etc.
The apparatus according to the invention is further adapted to be selectively linked with external devices so as to operate in cooperation with same. By way of example, the apparatus of the invention may be connected with an automatic sampler similar to that disclosed in the aforesaid U.S. Pat. Nos. 5,091,863 or 5,172,332. The user may then instruct the apparatus to initiate sampling operations by the automatic sampler on the basis of fluid flow related variables, or on the basis of high, low, or a range of critical levels of fluid condition(s) as calculated by the apparatus. The apparatus of the invention also automatically calculates and stores fluid flow-related variables and levels of fluid conditions to permit tracking of the history of the fluid conditions in a process stream.
The apparatus according to the invention may also be selectively connected to other external devices to initiate desired actions based on fluid flow-related variables or fluid condition(s) values calculated by the apparatus. For example, the apparatus may be connected with a pump so as to initiate pump operation when water level rises above a predetermined level. It is further contemplated that the apparatus according to the invention may be selectively connected with other external devices, such as a rain gauge, so as to log data therefrom.
2. Description of the Relevant Art
Under current governmental statutes and regulations, municipal agencies and private organizations are required to carefully monitor fluid waste. Monitoring is also conducted for pollution research purposes and the like. By way of example, monitoring is typically conducted in the following applications: monitoring for compliance with NPDES permits; POTW compliance monitoring; storm water run-off monitoring; combined sewer overflow ("CSO") monitoring; pretreatment compliance; WWTP process control; and infiltration and inflow studies.
In these and similar monitoring applications, one of the principal devices used on-site is a flow meter. In addition to monitoring various fluid flow-related variables, the flow meter may also be used for pacing sampling operations in proportion to flow rate, i.e., in conjunction with a sampling apparatus which repeatedly collects samples for subsequent laboratory analysis. A separate analytical meter is also often used for on-site monitoring of critical fluid conditions, such as pH level or ORP, to alert the user in a relatively immediate fashion to an upset in the process stream. Because flow meters, analytical devices and samplers are regularly transported to and mounted at remote field sites, it is desirable for each piece of equipment to be as compact, versatile, and easy to use as possible.
The present inventors, in the apparatus disclosed in their aforesaid U.S. Pat. No. 5,091,863, have overcome many of the problems associated with using separate samplers and flow meters by providing an integrated, compact automatic sampling and flow measuring apparatus capable of pacing sampling in proportion to flow rate, and of storing sample collection and flow data for retrieval in hard copy form.
In the apparatus disclosed in their aforesaid U.S. Pat. No. 5,172,332, the present inventors have also overcome the problems associated with separate automatic sampler and analytical meter devices. The apparatus combines a sampler and analytical meter in a single unitary structure, with the sampler and analytical meter sharing the same computer control means, digital display, keyboard, circuitry, etc. The computer control means of the apparatus automatically calculates the values of fluid condition(s) such as pH level, and controls sampling operations on the basis of time and/or fluid condition(s). The apparatus also stores sample collection and fluid condition(s) data for later retrieval by the user.
The multi-function apparatus of the present invention is particularly directed to solving problems associated with transporting and using flow meters at remote monitoring sites. Technicians in the field encounter a variety of different conditions at different sampling sites, sewer manholes, and other monitoring environments, so that different types of flow sensors are required to accommodate varying open channel flow applications. Heretofore, it has been necessary to use different flow meter devices, each adapted to operate with only a single sensor type, to accommodate varying field conditions. For example, where an ultrasonic flow sensor would be best suited for a particular application, the user would have to acquire and transport a separate flow meter having an ultrasonic flow sensor. Subsequently, if the user were to encounter field conditions for which a bubbler-type flow sensor would be most suitable, the user would have to acquire and transport a different flow meter having a bubbler-type sensor.
The expense and inconvenience entailed by the use of different flow meters is eliminated by the present invention, in which the same compact apparatus accommodates a variety of interchangeable flow sensors. The multi-function fluid monitoring apparatus of the present invention has a compact, unitary structure incorporating a microprocessor which is programmed to automatically calculate and store data, as well as to perform other functions. A principal advantage afforded by the present invention is that the same compact fluid monitoring apparatus accommodates a plurality of different types of interchangeable flow sensors. Other advantages afforded by the invention include the selective graphic or tabular display of stored data in a convenient form for the user, the capability of monitoring various fluid conditions in addition to fluid flow-related variables, and the ability to initiate actions by external devices linked to the fluid monitoring apparatus, such as sampling by an automatic sampler. These and other features of the apparatus according to the invention render it multi-functional and highly versatile in use, while providing a structure which is very compact, conveniently transportable, and minimizes expense.